Scientists plan mission to blow up an asteroid 'hurtling towards Earth'

[jimmydeanno]

http://news.discovery.com/space/is-star-treks-tractor-beam-possible.html

[♠SARKID♠]

Unless the added satellite is substantially more massive than the object you're trying to divert (not a trivial task), the paths would merely converge.

Unless the satellite is able to periodically use a thruster to maintain a constant distance.

[davidsinn]

Unless the added satellite is substantially more massive than the object you're trying to divert (not a trivial task), the paths would merely converge.

Unless the satellite is able to periodically use a thruster to maintain a constant distance.

The amount of energy needed to get the Δv required to lob an sufficiently massive object + fuel to an asteroid would be better spent just pushing the asteroid into a new orbit.

[tsrup]

Deep Impact followed a "tad" more believable storyline.

Of course there's a lot more science to blowing something up in space, blowing it up in space might actually make things worse.
Depends entirely on the composition, size etc of the object.

Another theory I like is, instead of blowing the thing up, pushing the object off course so it misses the Earth, though that doesn't sound as cool as blowing one up. 

Lots of research still needed.

Exactly.

Watch a video of skeet or trap shooting some time. The destroyed bird's fragments maintain the same trajectory as before, because of the differences in masses. Simply shattering it with a big explosion doesn't reduce the mass, or have a great effect on the trajectory.

This is where Deep Impact had things a bit better.  They wanted to split the object in half, each half passing on either side of Earth.  This obeys conservation of momentum, which is one of those rules you really can't ignore!  Now, the timeframe they had was wildly unrealistic and distorted to Hollywood specs, but the basic principle was not bad.

Isn't that what they wanted to do in Armageddon as well?

[MikeD]

http://www.youtube.com/watch?v=FXyaTwS5N10